NIR Stimulator Build

Most people are familiar with the terms hard science and soft science. A
hard science is one which is subject to rigorous quantitative
statistical analysis whereas a soft science more often deals with
qualitative intangibles. This “soft to hard” spectrum wasn’t developed
as a criticism. In fact, the developer of the idea, Auguste Comte is
considered the founder of sociology which in terms of scientific
hardness is found just above “paranormal investigation” and just below
talc. Another rather maligned science when viewed in terms of hardness
is psychology. Psychology often deals with totally qualitative factors
such as mood and mind; however, this isn’t to say that soft sciences
don’t contribute to humanity. In fact, many of the social ills we
experience are due to policies ignoring the findings of sociology,
psychology, and criminology. Furthermore, the hardness of a science
varies depending on the particular area of the umbrella under which one
stands. Sensory psychology studies phenomena which can be entirely
expressed quantitatively and thus stands as hard a science as biology.

In
the 1930’s, research by Wolfgang Metzger confirmed that hallucinations
and electroencephalogram changes consistently occur when a person is
subjected to a featureless field of vision. This study explained and
confirmed the hallucinations reported by Arctic explorers, trapped
miners, and those placed in sensory deprivation. The use of an EEG
provides reliable quantitative data which confirms the study as being
worthy of the label hard. To produce a featureless field, Metzger
used a Ganzfeld (German for “complete field”) stimulator, which
provides a uniform and featureless field of color. This design has been
further developed into multi-modal devices such as the “mind machine”
which uses a flickering Ganzfeld along with binaural beats as a means to
produce a drug free altered state of consciousness.

Ganzfeld
stimulators are also still used to study the electrical activity of the
eye. In electroretinography, the response of the retina is measured
while being subjected to a stimulus supplied by a Ganzfeld stimulator.
Unfortunately, for our purposes a normal Ganzfeld stimulator simply
isn’t adequate. The electrical response of retinal cells to the
stimulation of light are nearly uniform regardless of the wavelength
used. In order for our ERG data to be meaningful, and demonstrate that
the retina has developed sensitivity to previously undetectable near
infrared light, a new type of Ganzfeld stimulator had to be invented and
built. I present to you, the Gibson Rift.

OK, so
forgive my momentary lapse into grandiosity. The reality is that the
design is rather simple. It isn’t much more than a few infrared LEDs
blinking away inside crudely made fiberglass goggles which function to
block out ambient light. The device wasn’t actually named by any member
of team Science for the Masses either. It was deemed the Gibson Rift by
prominent biohackers Amal Graafstra and Rich Lee at a transhumanist
conference and the name just stuck. Going into this project, I had
nearly no knowledge regarding fiberglass fabrication or electronics and
hit a number of roadblocks. My hope is that this post helps others to
avoid such pitfalls should they want to repeat our research.

Construction of the Frame

The
frame was initially modeled in floral foam. The advantage of floral
foam is that it’s easy to work with and it doesn’t break down from the
solvents in fiberglass resin. The foam pieces can be glued together
using a hotglue gun. As long as the person for whom the device is being
constructed is present, it’s easy to cut and glue according to the size
of that person’s head. It was rather more laborious to construct the
frames from measurements, but if need be the ratio of head width to
length tends towards 2:3. So if a person’s head is measured from front
to back as being 9 inches,
the width tends to be around 6 inches. This approximation allows a
person to extrapolate size from circumference. Don’t put too much effort
into shaping the foam as features will be lost underneath the
fiberglass and you’ll just need to shape them again later.

After
roughing out the foam, apply a layer of resin followed with a layer of
fiberglass cloth and another layer of resin. Fiberglass supplies can be
purchased from nearly any hardware store. I advise purchasing an extra
container of hardener and mixing the resin “hot” meaning with a larger
proportion of hardener. It’s much easier to sand off a mistake that
hardened too soon than it is to fix the wet droopy mess that results
from too “cold” of a resin. Fiberglass resin hardens much faster at
higher temperatures and under UV light, so this isn’t a rainy winter day
project. After the initial coat hardens, grind and cut out features
such as the anterior space which holds the electronics, the eyecup which
holds the IR filter lens and the IR LEDs, and the mounting bolt for the
straps.

When
people fix automotive projects with fiberglass, Bondo is a BIG time
saver. Because our project is so small though, I found that an
airdryable lightweight modeling medium works much better. Don’t worry
about small mistakes such as areas with minimal resin, cracks, and
places where you sanded the material too thin. Fill in mistakes and
shape out features using this airdry clay and then apply another layer
of fiberglass and resin. Be far more cautious when applying this layer
though, as it will be the final outer layer. Using long strips of cloth
rather than many smaller bits is also crucial as this is what will
provide a durable final product.

Peripherals

To
mount straps onto the frame, I used carriage bolts which, again, can be
purchased from nearly any hardware store. Carriage bolt have a long
area sans threads, so once installed and glued into the frame, you’re
left with a nice smooth surface for the straps to rest on. I first
drilled appropriately sized holes into the frame on the left and right posterior
regions and through the portions of the frame which extend out of the
superior surface. I used an epoxy glue to secure the bolts and then used
a grinder to remove the portions of the bolts which extended beyond the
desired size of the frame.

For the anterior box, I
chose an L arranged conduit body. This is intended to be used for
industrial and home wiring as an area in which one can splice wires. It
allows for easy access and installation of our electronic guts. Prior to
attaching this piece, I drilled appropriately sized holes along the
superior surface so that I could later install the switches that control
the IR LEDs.I hot glued the conduit body to the anterior of the device
with one of the tubes passing through the portion that will serve as our
right eye piece. I mounted a project box at the end of the other tube
and drilled a hole so that wires could be passed through.

After
attaching these peripherals, fill in any gaps between that part and the
body with more airdry clay, and apply your final resin coat. If you
want it to look pretty, feel free to spray on some color and a layer of
clear gloss coat. The last peripheral portion to be attached is the IR
filter lens, but this shouldn’t be done until the electronic portion has
been installed as it will prevent you from being able to arrange the
LEDs.

Circuit and Switches

To
drive our LEDs, I found a number of different tutorials using an 8 pin
555 IC. There are a vast number of “instructables” on the subject and
damn near everyone is different. This image shows the circuit I settled
on. This post isn’t intended to teach people to solder or work with
electronics, but I’ll tell you lessons that I learned: Solder isn’t
meant to physically hold things together. Secure your wires and pins
mechanically first. Not a single one of those conductive pastes or pens
is worth a damn, so don’t waste your money. And finally, it’s totally
worth your while to start with a breadboard and make a mock up first. I
promise it will save you from later frustrations.

Instead
of directly mounting the LEDs to the board or soldering leads running
off the board, just use terminal blocks. Make a second simple board on
which to mount the LEDs and then add the wires between later. I know
everything I’m saying is remedial to those who are into circuit
building, but no one ever gave me this advice, and I earned the
knowledge through hours of frustration. And finally, because of the size
constraints of the boxes on the front of the device, you’ll need to
make sure your circuit board is going to fit prior to actually
assembling it. A very strange thing to me, is that the sizes of project enclosures
available at Radioshack, don’t match any of the blank circuit boards. I
ground the circuit boards down to the appropriate size prior to
assembly and it worked fine.

This 8 pin 555 IC
circuit results in LEDs which flash at a set rate. The reason that you
want the LEDs to flash rather than simply glow, is that we are looking
for an A/B signal response in our ERG data. If we find A/B fluctuations
which match the flash rate of the NIR LEDs, this confirms that our
retinal cells have gained sensitivity.

After
assembly, simply mount your driver circuit in the project box, the
switches into the holes along the conduit box, and the LED board should
fit right into the tubing anterior to the eye piece.

The
LEDs used in our project have peak emissions at 850nm, 950nm, 1070nm,
and 1200nm. To test the LEDs, you unfortunately won’t be able to use
your bare eyes, except for the 850nm. Although 850nm is beyond the range
of normal human vision, LEDs emit light within a narrow wavelength
range. While the lowest wavelength LED may peak
at 850nm, the lower range of its emission pattern does extend down into
the visual range. This actually works to our benefit, in terms of
testing, in that the final LED to be activated serves as a control from
which we can determine the expected retinal response. If and when our
retinal cells gain sensitivity into the ranges of the other NIR LEDs,
they will elicit a similar ERG signal. In order to test the 950nm,
1070nm, and 1200nm LEDs one can use a digital camera. The majority of
cheap digital camera can pick up wavelengths into the NIR. Smartphone
cameras will also suffice. After attaching your electronic guts, hot
glue the IR filter lens in front of the LEDs immediately before where
your eye will rest.

Foam Padding and Straps

Strangely
enough, this was one of the more difficult issues to solve. A
compressible foam layer that blocks light is critical. I tried
everything from carving silicone to felt covered foam, but nothing
seemed adequate until I started

reading
blogs by people who are into cosplay. People build these huge elaborate
suits ranging from knight’s armor to giant Teenage Mutant Ninja Turtle
heads. Furthermore, they build these things to sustain some serious
beating albeit with foam ninja swords. The best solution I found was to
cut and glue together pieces of EVA foam to build up the eye pad shape.
Then, alternate between spraying on layers of 3M adhesive and Plasti
Dip. It really does take a rather surprising number of coats. The first
three coats end up being absorbed by the foam and it isn’t until coat 5
or 6 that the eye piece really starts to look promising. By coat ten or
so, you end up with a pliable soft rubbery eye piece that suits our
purposes for blocking out ambient light with some degree of comfort. Hot
glue this eyepiece into the frame and your device is nearly ready.

After
the previous steps, sewing the straps together will be easy as pie. I
used 1” black nylon straps and arranged them with one that goes over
the head and attaches to the strap that wraps around the sides of the
head. I used two buckles to make adjustment easy. Once attached, your
“Gibson Rift” is complete.

Overall, construction of
our stimulators was an educational experience for me. Because we knew
going into this process, that there was bound to be a considerable
amount of waste from failed prototypes, we chose to fund construction
primarily with our own funds rather than the donated funds. The one
exception to this was the 1070nm and 1200nm NIR infrared LEDs which at
26$ a piece were far costlier than originally expected. These devices
have been tested and function as expected and will fulfill the needs of
our project. Furthermore, the experience has lead to skills in both
electronics and fiberglass fabrication which will likely be of great use
in our future Science for the Masses endeavors.